Flat panel displays, such as liquid crystal display (LCD), micro light-emitting diode (LED) display, organic light-emitting diode (OLED) display, and electroluminescent display (ELD), are information viewing technologies for widespread use in a variety of electronic apparatus, as the characteristics of thinness, light weight and low dissipation power are widely recognized. These flat panel displays, generally, manufactured and sold today is mounted on rigid glass substrates. Glass substrates can be processed at high temperatures, provide a surface made very smooth and uniform even over large areas, and have desirable optical properties such as high transparency. Although these features are suitable for the manufacture of certain flat panel displays, the rigidness of glass restricts applications of displays configured on non-planar or rugged surfaces and is subject to easy breakage.
As demand for showing information on the diverse surfaces of electronic apparatus is recently increasing, it would be desirable, for many applications, to have flexible or foldable displays that can be bent to a radius of curvature of centimeters without losing functionality. Use of flexible substrates, such as resin, to simply replace glass substrate with a flat panel display is an approach to achieve the flexibility. The flexible substrates can enable or improve the production of flat panel displays and make these displays to conform to any desired shape, so as to substantially broaden their applications.
However, despite the above-mentioned advantages of flexible substrates, a new challenge appears. The flexible substrates are vulnerable to external force, such as scratch and friction. Therefore, there remains a need for improving flexible flat panel displays that ameliorate or eliminate the problem of the flexible substrate.